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Helios-40....Yellow cast/Yellow glass
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PostPosted: Sat Jan 19, 2008 9:54 pm    Post subject: Helios-40....Yellow cast/Yellow glass Reply with quote

My recently acquired Helios-40 is giving a very strong yellow cast to all its pics. I cannot see anything wrong with the glass. Ideas? Solutions? Cures?


Shocked Shocked patrickh


PostPosted: Sat Jan 19, 2008 10:32 pm    Post subject: Reply with quote

Some 50mm f1.4 screw mount Takumars were known to do this because they contained a radioactive element that turned the glass very slightly yellow over time. This may not be too noticeable when looking thru the lens depending on what color the coating is. Do you know if your Helios is known for the same issue. (I have never heard that it is but I suppose its an obvious question to ask.)

The only other things I can think to ask are (a) under what conditions were the pictures taken (nothing obvious like under tungsten lights???) (b) Were you using film and if so what about the film you were using (was it old / new / properly stored?) and finally who processed the films for you. (I suppose there is a chance of a processing error.)

I recall years ago using a nice Pentax K2 with a 50mm f1.4 lens that I had bought and being very disappointed to find that all the shots taken had a kind of sepia tinge over the colors. I sold the camera a short while later to finance another camera and never got to the bottom of why this was so but suspect that it could have been poor developing / printing.


PostPosted: Sat Jan 19, 2008 11:03 pm    Post subject: Reply with quote

Used on the Oly 300 digital. Several other lenses used at the same time - outdoors, full sun. Only the Helios had this cast. Very disappointing. Perhaps a week or two in the sunshine, but I thought that was for radioactive or rare earth lenses and I dont know if the Helios is one of those.


patrickh


PostPosted: Sat Jan 19, 2008 11:28 pm    Post subject: Reply with quote

Helios-40 has normal glass not yellowing at all at least mine not yellow at all. Orio has at least two copies also not yellowed, sorry about your trouble Patrick, best to send back if you can.


PostPosted: Sun Jan 20, 2008 2:04 am    Post subject: Reply with quote

I guess the answer has to lie in the lens somewhere then. I have not heard of these having a radio active yellowing issue either but thought I should ask. I am not sure where to from here. But if you got the elns at an Ok price and you are shooting digital anyway you could just reconcile yourself to the problem and use photoshop to fix the cast in post processing. Its pretty common for me to have to fix the color in in a photo in one way or another in any event.


PostPosted: Sun Jan 20, 2008 2:25 am    Post subject: Reply with quote

Sorry to hear that. Russians are known to put many many different coatings on their lenses...there are green, gold, blue, orange, and purple cast ones. Some are rare to see on particular lenses but I have a feeling that if the lens had a long production run (like the helios 40s) they may have had a run in with all of these coatings at one time or another. So depending on what cast your lens has, it could possibly effect the pictures overall tone.

I have to say though a good soaking up of some sun never hurt any lens, as long as you don't let it get hot, because then old grease can become thin and run. Frankly, who knows what the Russians did with their coatings...maybe some of them were radioactive/rare earth. So just because the most common ones don't have this problem, doesn't mean it isn't a problem with some.

~Marc


PostPosted: Sun Jan 20, 2008 3:22 am    Post subject: Reply with quote

Attila wrote:
Helios-40 has normal glass not yellowing at all at least mine not yellow at all. Orio has at least two copies also not yellowed


Well, actually this is not really correct. I used to have three copies, but not together, in different times (now I own only one) and yes the Helios-40 has a slightly warmer tone than the Helios-40-2, although never as bad as the SMC Takumar 1.4/50 that I have.
I have cured my first Helios copy with the sun and it has bettered considerably. So yes sun-tan is the answer.


PostPosted: Sun Jan 20, 2008 3:38 am    Post subject: Reply with quote

Thank you all - I will put it in the sun - whenever it comes out again. Today it goes away for the next three days and we have snow on the way. I think I shalkl like this lens when I fix it - it has a very pleasing "softness" about it without losing any detail.


PostPosted: Sun Jan 20, 2008 4:31 pm    Post subject: Reply with quote

No sun so I will cook it with an ultra violet lamp, which I am told should work. I did more checking by comparing a similar shot taken at the same time (same light) of the same building, and which I knew was accurate for colour. It turns out that the yellow cast makes an upward light difference of 2000Kelvin! I had to reset bright sun from an approximate 5100K down to 3100K and reduce the yellow tinting as well to get it right. Extraordinary, I would send it back but I think it is fixable and the lens is in lovely condition apart from this.


patrickh


PostPosted: Sun Jan 20, 2008 6:17 pm    Post subject: Reply with quote

Cool! I am so glad!


PostPosted: Sun Jan 20, 2008 7:47 pm    Post subject: Reply with quote

Yellowing also seems to affect the zebra Pancolars but not the later all black copies.


PostPosted: Sun Jan 20, 2008 7:49 pm    Post subject: Reply with quote

I saw only 1.4 Pancolar in yellow , but not effect picture quality.


PostPosted: Sun Jan 20, 2008 7:51 pm    Post subject: Reply with quote

My 1.8/50 zebra M42 is yellow, but none of my two 2/50 Exaktas are, neither is the black 1.8/50.


PostPosted: Sun Jan 20, 2008 8:01 pm    Post subject: Reply with quote

You are not lucky really I saw quite a lot Pancolar 1.8 none of them was yellow.


PostPosted: Sun Jan 20, 2008 9:20 pm    Post subject: Reply with quote

I've read posts on other forums about yellow Pancolars, in particular the zebras. That, and the fact that I ended up with a yellow copy myself is enough for me to at least ask sellers in future about it.

I've had my copy sitting on top of a blacklight for the last three weeks or so and the yellowing has noticeably decreased although I don't think the black light is powerful enough to take things further.


PostPosted: Sun Jan 20, 2008 9:34 pm    Post subject: Reply with quote

bob955i wrote:
I've read posts on other forums about yellow Pancolars, in particular the zebras. That, and the fact that I ended up with a yellow copy myself is enough for me to at least ask sellers in future about it.

I've had my copy sitting on top of a blacklight for the last three weeks or so and the yellowing has noticeably decreased although I don't think the black light is powerful enough to take things further.


I've got one of these, but in 400W - I'm itching for a yellow lens to put in front of it.
http://www.venturelighting.com/TechCenter/Metal-Halide-TechIntro.html


PostPosted: Sun Jan 20, 2008 10:18 pm    Post subject: Reply with quote

Farside
Will a metal halide lamp produce the right kind of light to disperse whatever is causing the yellow cast?


patrickh


PostPosted: Sun Jan 20, 2008 10:46 pm    Post subject: Reply with quote

patrickh wrote:
Farside
Will a metal halide lamp produce the right kind of light to disperse whatever is causing the yellow cast?


They produce large amounts of UV, but that's before the two glass filters go in front of them - one around the body of the lamp itself (believe me, you don't want to remove that one) and the other glass plate in the front of the luminaire. I was thinking of removing the glass weather plate and exposing a lens to the lamp that way. I have a luminaire set up so it's portable and can easily be turned on/off remotely just in case.
The front weather glass also acts as an explosion shield, so you never know.
Distance is the key - don't want to sit the lens too close, because the heat is significant and oil/grease vapourisation may occur, just the right distance and it should be ok.

I'd be inclined to experiment with a non-valuable lens first, though.

Here's one I have...



PostPosted: Mon Jan 21, 2008 5:10 am    Post subject: Reply with quote

I am neither daring nor manually proficient - I think I shall just buy a powerful UV lamp Shocked Shocked Shocked


patrickh


PostPosted: Mon Jan 21, 2008 5:16 am    Post subject: Reply with quote

I'm getting visions of photographers contacting their local tanning studio and saying I want to book a sunbed, but it's not for me...' Very Happy